Organic light emitting display device and manufacturing method for the same

ABSTRACT

An organic light emitting display device includes a substrate, a thin film transistor formed on the substrate and including an active layer, a gate electrode including a gate lower electrode and a gate upper electrode, a source electrode, and a drain electrode, an organic light emitting device electrically connected to the thin film transistor, wherein a pixel electrode formed of the same material as at least a part of the gate electrode in the same layer, an intermediate layer including a light emitting layer, and an opposed electrode arranged to face the pixel electrode are sequentially deposited.

CLAIM OF PRIORITY

This application makes reference to, incorporates the same herein, andclaims all benefits accruing under 35 U.S.C. §119 from an applicationearlier filed in the Korean Intellectual Property Office on 8 Dec. 2010and there duly assigned Serial No. 10-2010-0124863.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an organic light emitting displaydevice and a manufacturing method thereof, and more particularly, to anorganic light emitting display device having a simplified manufacturingprocess and satisfying all of a patterning characteristic, an electricalcharacteristic, and a pad reliability of a pad unit, and a method ofmanufacturing the organic light emitting display device.

2. Description of the Related Art

Flat panel display devices such as organic light emitting displaydevices or liquid crystal display devices are manufactured on asubstrate on which a pattern including thin film transistors (TFTs),capacitors, and wiring connecting the TFTs and capacitors is formed. Ingeneral, to form a fine pattern including TFTs on a substrate on which aflat panel display device is manufactured, the pattern is transferred tothe substrate by using a mask where the fine pattern is formed.

A process to transfer a pattern using a mask generally uses aphotolithography process. According to the photolithography processincluding a series of sub-steps, photoresist is uniformly formed on asubstrate on which a pattern is to be formed. The photoresist is exposedto light using an exposure equipment such as a stepper. In the case ofpositive photoresist, the exposed photoresist is developed. After thephotoresist is developed, the pattern is etched using the remainingphotoresist as a mask, thereby removing unnecessary photoresist.

In the process of transferring a pattern using a mask, a mask having anecessary pattern thereon is needed. Accordingly, as the number of stepsin which a mask is used increases, a manufacturing cost for preparing amask increases. Also, since the above-described complicated steps areneeded, a manufacturing process is complicated, a manufacturing time isextended, and a manufacturing cost rises.

SUMMARY OF THE INVENTION

To solve the above and/or other problems, the present invention providesan organic light emitting display device having a simplifiedmanufacturing process and satisfying all of a patterning characteristic,an electrical characteristic, and a pad reliability of a pad unit, and amethod of manufacturing the organic light emitting display device.

According to an aspect of the present invention, an organic lightemitting display device includes a substrate, a thin film transistorformed on the substrate and including an active layer, a gate electrodeincluding a gate lower electrode and a gate upper electrode, a sourceelectrode, and a drain electrode, an organic light emitting deviceelectrically connected to the thin film transistor, wherein the organiclight emitting device includes a pixel electrode formed of the samematerial as at least a part of the gate electrode in the same layer, anintermediate layer including a light emitting layer, and an opposedelectrode arranged to face the pixel electrode are sequentiallydeposited, and a first pad electrode formed of the same material as thegate upper electrode in the same layer, and a second pad electrodeformed of the same material as the source electrode and the drainelectrode in the same layer and including an ion doped layer in whichpredetermined ions are doped in a surface opposite to a surface facingthe substrate.

The first pad electrode may include molybdenum (Mo).

The second pad electrode may include aluminum (Al).

The ions doped in the ion doped layer may include at least one of nickel(Ni) and lanthanum (La) ions.

The ions may be doped only in a surface and an adjacent area of thesecond pad electrode opposite to a surface facing the substrate.

The ion doped layer may be formed by an ion implantation process.

The ion doped layer may not be formed in the source electrode and thedrain electrode.

The second pad electrode may be exposed to the outside.

The organic light emitting display device may further include a padlower electrode formed of the same material as the gate lower electrodeand the pixel electrode in the same layer and interposed between thesubstrate and the first pad electrode.

The gate lower electrode, the pixel electrode, and the pad lowerelectrode may include at least one of ITO, IZO, ZnO, and In₂O₃.

The organic light emitting display device may further include a storagecapacitor that includes a capacitor lower electrode formed of the samematerial as the active layer in the same layer and a capacitor upperelectrode formed of the same material as the gate lower electrode in thesame layer.

The organic light emitting display device may be of a bottom emissiontype in which an image is presented toward the substrate.

According to another aspect of the present invention, an organic lightemitting display device includes a first insulation layer formed on asubstrate, an active layer formed on the first insulation layer, asecond insulation layer covering the active layer, a pixel electrodeformed on the second insulation layer, a gate lower electrode formed ofthe same material as the pixel electrode in the same layer above theactive layer by being separated a predetermined distance from the pixelelectrode, and a pad lower electrode formed of the same material as thegate lower electrode in the same layer by being separated apredetermined distance from the gate lower electrode, a gate upperelectrode formed on the gate lower electrode, and a first pad electrodeformed of the same material as the gate upper electrode in the samelayer on the pad lower electrode, a third insulation layer covering atleast a part of the pixel electrode, the gate upper electrode, and thefirst pad electrode, and source and drain electrodes formed on the thirdinsulation layer by contacting the pixel electrode, and a second padelectrode formed of the same material as the source and drain electrodesin the same layer on the first pad electrode, wherein an ion doped layerin which predetermined ions are doped is formed in an upper portion ofthe second pad electrode.

The first pad electrode may include molybdenum (Mo), the second padelectrode may include aluminum (Al), and the ions doped in the ion dopedlayer may include at least one of nickel (Ni) and lanthanum (La) ions.

The ions may be doped only in a surface and an adjacent area of thesecond pad electrode opposite to a surface facing the substrate.

According to another aspect of the present invention, a method ofmanufacturing an organic light emitting display device includes formingan active layer on a substrate via a first mask process operation,forming a gate electrode and a first pad electrode via a second maskprocess operation, and an electrode pattern that forms a pixelelectrode, above the active layer, forming an interlayer insulationlayer having an opening that exposes both sides of the active layer viaa third mask process operation, a part of the first pad electrode, and apart of the electrode pattern, forming source and drain electrodescontacting both exposed sides of the active layer via a fourth maskprocess operation, a second pad electrode contacting an exposed part ofthe first pad electrode, and the pixel electrode, forming a pixel definelayer that exposes at least a part of the pixel electrode and at least apart of the second pad electrode via a fifth mask process operation, anddoping predetermined ions in at least a part of the exposed second padelectrode.

The doping of predetermined ions in at least a part of the exposedsecond pad electrode may be performed by an ion implantation process.

The ion implantation process may be performed by applying anacceleration voltage of about 10-40 keV.

In the doping of predetermined ions in at least a part of the exposedsecond pad electrode, the ions may be doped only in a surface and anadjacent area of the second pad electrode opposite to a surface facingthe substrate.

The doping of predetermined ions in at least a part of the exposedsecond pad electrode may be performed in a state in which the source anddrain electrodes are covered by the pixel define layer.

The first pad electrode may include molybdenum (Mo), the second padelectrode may include aluminum (Al), and the ions doped in the ion dopedlayer may include at least one of nickel (Ni) and lanthanum (La) ions.

An annealing process operation of diffusing the injected ions may beperformed after the doping of predetermined ions in at least a part ofthe exposed second pad electrode

The second mask process operation may include sequentially depositing asecond insulation layer, a first conductive layer, and a secondconductive layer above the active layer, and forming the gate electrodeincluding the first conductive layer as a gate lower electrode and thesecond conductive layer as a gate upper electrode and simultaneouslyforming the first conductive layer as a pad lower electrode and thesecond conductive layer as a first pad electrode, by patterning thefirst conductive layer and the second conductive layer.

The third mask process operation may include depositing a thirdinsulation layer on the gate electrode, the first pad electrode, and theelectrode pattern, and forming an opening by patterning the thirdinsulation layer, the opening exposing parts of source and drain regionsof the active layer, a part of the first pad electrode, and a part ofthe electrode pattern.

The fourth mask process operation may include depositing a thirdconductive layer on the interlayer insulation layer, and forming thesource and drain electrodes and the second pad electrode by patterningthe third conductive layer.

The fourth mask process operation may further include forming the sourceand drain electrodes and the second pad electrode, and forming the pixelelectrode including the first conductive layer as an electrode byremoving the second conductive layer constituting the electrode pattern.

The fifth mask process operation may include depositing a fourthinsulation layer on an entire surface of the substrate, and forming thepixel define layer by patterning the fourth insulation layer.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention, and many of the attendantadvantages thereof, will be readily apparent as the same becomes betterunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings in which likereference symbols indicate the same or similar components, wherein:

FIG. 1 is a plan view schematically illustrating the structure of anorganic light emitting display device according to an embodiment of thepresent invention;

FIG. 2 is a cross-sectional view taken along a line II-II of FIG. 1;

FIGS. 3-12 are cross-sectional views for schematically illustrating aprocess of manufacturing the organic light emitting display device ofFIG. 2;

FIG. 13 schematically illustrates the shape of a pad electrode of anorganic light emitting display device manufactured by a manufacturingmethod of the present invention;

FIG. 14 schematically illustrates the shape of a pad electrode of aconventional organic light emitting display device, in which the padelectrode is formed in a tri-layer structure of molybdenum (Mo)-aluminum(Al)-molybdenum (Mo);

FIG. 15 is a graph showing a concentration profile according to a depthafter an ion implantation process; and

FIG. 16 is a graph showing a concentration profile according to a depthafter an annealing process is performed.

DETAILED DESCRIPTION OF THE INVENTION

The attached drawings for illustrating exemplary embodiments of thepresent invention are referred to in order to gain a sufficientunderstanding of the present invention, the merits thereof, and theobjectives accomplished by the implementation of the present invention.Hereinafter, the present invention will be described in detail byexplaining exemplary embodiments of the invention with reference to theattached drawings Like reference numerals in the drawings denote likeelements.

FIG. 1 is a plan view schematically illustrating the structure of anorganic light emitting display device 1 according to an embodiment ofthe present invention. Referring to FIG. 1, the organic light emittingdisplay device 1 according to the present embodiment includes a firstsubstrate 10 including a thin film transistor (TFT) and a light emittingpixel, and a second substrate 20 that is coupled to the first substrate10 via sealing.

The TFT, an organic electroluminescent device EL, and a storagecapacitor Cst may be formed on the first substrate 10. Also, the firstsubstrate 10 may be a low temperature poly silicon (LTPS) substrate, aglass substrate, a plastic substrate, or a stainless using steel (SUS)substrate.

The second substrate 20 may be an encapsulation substrate that isarranged on top of the first substrate 10 to shield the TFTs and thelight emitting pixels provided on the first substrate 10 from externalmoisture or air. The second substrate 20 is disposed to face the firstsubstrate 10, and the first and second substrates 10 and 20 are combinedwith each other via a sealing member 90 that is arranged along the edgethereof. The second substrate 20 may be a transparent glass or plasticsubstrate.

The first substrate 10 includes a light emitting area DA from whichlight is emitted and a non-light emitting area NDA that is disposedoutside the light emitting area DA. According to the embodiments of thepresent invention, as the sealing member 90 is arranged in the non-lightemitting area NDA outside the light emitting area DA, the first andsecond substrates 10 and 20 are combined together.

As described above, the EL, the TFT that drives the EL, and a wiringelectrically connected to the components are formed in the lightemitting area DA. The non-light emitting area NDA may include a pad area5 where a pad electrode extending from the wiring of the light emittingarea DA is disposed.

In the organic light emitting display device according to the presentembodiment, the pad area 5 includes a first pad electrode and a secondpad electrode, and an ion doped layer is provided in an upper portion ofthe second pad electrode. The structure of the pad electrode having theabove structure will be described below in detail.

FIG. 2 is a cross-sectional view taken along a line II-II of FIG. 1.Referring to FIG. 2, the organic light emitting display device 1according to the present embodiment includes a channel area 2, a storagearea 3, a light emitting area 4, and a pad area 5.

A TFT is provided as a driving device in the channel area 2. The TFTincludes an active layer 212, a gate electrode 21 g, and source anddrain electrodes 217 a and 217 b. The gate electrode 21 g includes agate lower electrode 214 and a gate upper electrode 215. The gate lowerelectrode 214 may be formed of a transparent conductive material. Asecond insulation layer 13 for insulation between the gate electrode 21g and the active layer 212 is provided therebetween. Source and drainregions 212 a and 212 b in which high concentration impurities areinjected are formed at both sides of the active layer 212 and arerespectively connected to the source and drain electrodes 217 a and 217b.

The storage capacitor Cst is provided in the storage area 3. The storagecapacitor Cst includes a capacitor lower electrode 312 and a capacitorupper electrode 314. The second insulation layer 13 is interposedbetween the capacitor lower electrode 312 and the capacitor upperelectrode 314. The capacitor lower electrode 312 may be formed of thesame material as the active layer 212 of the TFT in the same layer. Thecapacitor upper electrode 314 may be formed of the same material as thegate lower electrode 214 of the TFT, a pixel electrode 414 of the EL,and a pad lower electrode 514, in the same layer.

The EL is provided in the light emitting area 4. The EL includes thepixel electrode 414 connected to one of the source and drain electrodes217 a and 217 b of the TFT, an opposed electrode 420 formed to face thepixel electrode 414, and an intermediate layer 419 interposed betweenthe pixel electrode 414 and the opposed electrode 420. The pixelelectrode 414 may be formed of a transparent conductive material, andmay be formed of the same material as the gate lower electrode 214 ofthe TFT in the same layer.

The pad area 5 includes the pad lower electrode 514, a first padelectrode 515, and a second pad electrode 517. The pad lower electrode514 may be formed of the same material as the gate lower electrode 214of the TFT, the capacitor upper electrode 314, and the pixel electrode414 of the EL, in the same layer. Also, the first pad electrode 515 maybe formed of the same material as the gate upper electrode 215 in thesame layer. Also, the second pad electrode 517 may be formed of the samematerial as the source and drain electrodes 217 a and 217 b in the samelayer. Hereinafter, the first pad electrode 515 and the second padelectrode 517 together are referred to as a pad electrode.

The organic light emitting display device according to the presentembodiment includes the first pad electrode 515 and the second padelectrode 517 and an ion doped layer 517 a is formed on an upper portionof the second pad electrode 517. That is, in the organic light emittingdisplay device according to the present embodiment, the second padelectrode 517 is formed of the same material as the source drainelectrodes 217 a and 217 b in the same layer, and the ion doped layer517 a is formed on a surface of the second pad electrode 517, therebysatisfying all of a patterning characteristic, an electriccharacteristic, and a pad reliability. That is, the ion doping layer 517a that has a low resistance and simultaneously capable of functioning asa capping layer is formed by doping ions such as nickel (Ni) orlanthanum (La) ions in the upper portion of the second pad electrode 517formed of a material such as aluminum. A method of forming the iondoping layer 517 a and an effect thereof will be described in detailwith reference to FIG. 12. Although FIG. 2 illustrates that the secondpad electrode 517 and the ion doped layer 517 a are layers separatedfrom each other, it can be said that the ion doped layer 517 a isincluded in the second pad electrode 517 because the ion doped layer 517a is a layer that is obtained as a part of the second pad electrode 517is changed by doping ions such as nickel (Ni) or lanthanum (La) into thesecond pad electrode 517.

A process of manufacturing the organic light emitting display device ofa rear surface emission type shown in FIG. 2 will be described below.FIGS. 3-12 are cross-sectional views schematically illustrating aprocess of the organic light emitting display device of a rear surfaceemission type shown in FIG. 2.

First, as illustrated in FIG. 3, a first insulation layer 11 is formedon a substrate 10. In detail, the substrate 10 may be formed of atransparent glass material having a main component of SiO₂. Thesubstrate 10 is not limited thereto and a variety of substrates formedof various materials such as a transparent plastic material or a metalmember may be used.

The first insulation layer 11 such as a barrier layer and/or a bufferlayer for preventing diffusion of impurity ions, preventing intrusion ofmoisture or external air, and planarizing a surface of the substrate 10may be provided on an upper surface of the substrate 10. The firstinsulation layer 11 may be deposited using SiO₂ and/or SiN_(x) by avarious deposition methods such as a plasma enhanced chemical vapordeposition (PECVD) method, an atmospheric pressure CVD (APCVD) method,or a lower pressure CVD (LPCVD) method.

Next, as illustrated in FIG. 4, the active layer 212 of the TFT and thecapacitor lower electrode 312 of the storage capacitor Cst are formed onan upper surface of the first insulation layer 11. In detail, amorphoussilicon is first deposited on the upper surface of the first insulationlayer 11, and then the amorphous silicon is crystallized to form apolycrystal silicon layer (not shown). The amorphous silicon may becrystallized by a variety of methods such as a rapid thermal annealing(RTA) method, a solid phase crystallization (SPC) method, an excimerlaser annealing (ELA) method, a metal induced crystallization (MIC)method, a metal induced lateral crystallization (MILC) method, or asequential lateral solidification (SLS) method. The polycrystal siliconlayer is patterned into the active layer 212 of the TFT and thecapacitor lower electrode 312 of the storage capacitor Cst via a maskprocess using a first mask (not shown).

In the present embodiment, the active layer 212 and the capacitor lowerelectrode 312 are separated from each other, but the active layer 212and the capacitor lower electrode 312 may be formed in one body. Next,as illustrated in FIG. 5, the second insulation layer 13, a firstconductive layer 14, and a second conductive layer 15 are sequentiallydeposited on the entire surface of the substrate 10 where the activelayer 212 and the capacitor lower electrode 312 are formed.

The second insulation layer 13 may be formed by depositing an inorganicinsulation layer such as SiN_(x) or SiO_(x) in a method such as a PECVDmethod, an APCVD method, or an LPCVD method. The second insulation layer13 is interposed between the active layer 212 of the TFT and the gateelectrode (refer to 21 g of FIG. 2) and functions as a gate insulationlayer of the TFT, and also interposed between the capacitor upperelectrode (refer to 314 of FIG. 2) and the capacitor lower electrode 312and functions as a dielectric layer of the storage capacitor Cst.

The first conductive layer 14 may include one or more materials selectedfrom a group consisting of transparent materials including ITO, IZO,ZnO, or In₂O₃. The first conductive layer 14 may be patterned later intothe pixel electrode 414, the gate lower electrode 214, the capacitorupper electrode 314, and the pad lower electrode 514.

The second conductive layer 15 may include one or more materialsselected from a group consisting of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir,Cr, Li, Ca, Mo, Ti, W, MoW, and Al/Cu. The second conductive layer 15may be patterned later into the gate upper electrode 215 and the firstpad electrode 515. The second conductive layer 15 may be molybdenum(Mo).

Next, as illustrated in FIG. 6, the gate electrode 21 g, electrodepatterns 30 and 40, the pad lower electrode 514, and the first padelectrode 515 are formed on the substrate 10. In detail, the firstconductive layer 14 and the second conductive layer 15, which aresequentially deposited on the entire surface of the substrate 10, arepatterned by a mask process using a second mask (not shown).

The gate electrode 21 g is formed on an upper surface of the activelayer 212 in the channel area 2. The gate electrode 21 g includes thegate lower electrode 214 constituting as a part of the first conductivelayer 14 and the gate upper electrode 215 constituting as a part of thesecond conductive layer 15. The gate electrode 21 g is formedcorresponding to the center of the active layer 212. The source anddrain regions 212 a and 212 b are formed at both edges of the activelayer 212 corresponding to both sides of the gate electrode 21 g bydoping n-type or p-type impurities in the active layer 212 using thegate electrode 21 g as a mask, and the channel area 2 is formed betweenthe source and drain regions 212 a and 212 b.

The electrode pattern 30 for forming the capacitor upper electrode (314shown in FIG. 2) later is formed on an upper surface of the capacitorlower electrode 312 in the storage area 3. The electrode pattern 40 forforming the pixel electrode (414 shown in FIG. 2) later is formed in thelight emitting area 4.

The pad lower electrode 514 formed as a part of the first conductivelayer 14 and the first pad electrode 515 formed as a part of the secondconductive layer 15 are formed in the pad area 5. Although in thedrawings the electrode pattern 30 formed in the storage area 3 and thepad lower electrode 514 and the first pad electrode 515 formed in thepad area 5 are illustrated to be formed in one body, the presentinvention is not limited thereto and thus the electrode pattern 30formed in the storage area 3 and the pad lower electrode 514 and thefirst pad electrode 515 formed in the pad area 5 may be separatelyformed.

Next, as illustrated in FIG. 7, a third insulation layer 16 is depositedon the entire surface of the substrate 10 where the gate electrode 21 gis formed. The third insulation layer 16 is formed of one or moreorganic insulation materials selected from a group consisting ofpolyimide, polyamide, acryl resin, benzocyclobutene, and phenol resin,in a method such as spin coating. The third insulation layer 16 isformed to a sufficient thickness, for example, to be thicker than thesecond insulation layer 13, and functions as an interlayer insulationlayer (416 shown in FIGS. 2 and 8) between the gate electrode 21 g andthe source and drain electrodes (217 a and 217 b shown in FIG. 2) of theTFT. The third insulation layer 16 may be formed of not only theabove-described organic insulation material but also an inorganicinsulation material such as the second insulation layer 13, or formed byalternately arranging an organic insulation material and an inorganicinsulation material.

Next, as illustrated in FIG. 8, the interlayer insulation layer 416having openings H1, H2, H3, H4, H5, and H6 for exposing parts of theelectrode patterns 30 and 40 and the source and drain regions 212 a and212 b is formed by patterning the third insulation layer 16. In detail,the third insulation layer 16 is patterned by a mask process using athird mask (not shown), thereby forming the openings H1, H2, H3, H4, H5,and H6. The openings H1 and H2 expose parts of the source and drainregions 212 a and 212 b. The openings H3 and H4 expose a part of thesecond conductive layer 15 constituting the upper portion of theelectrode pattern 40. The opening H5 exposes a part of the secondconductive layer 15 constituting the upper portion of the electrodepattern 30. The opening H6 exposes a part of the first pad electrode515.

Next, as illustrated in FIG. 9, a third conductive layer 17 is depositedon the entire surface of the substrate 10 to cover the interlayerinsulation layer 16. The third conductive layer 17 may be formed of thesame conductive material as the above-described first or secondconductive layer 14 or 15. However, the present invention is not limitedthereto and the third conductive layer 17 may be formed of one selectedfrom a variety of conductive materials. The third conductive layer 17may include aluminum Al having a low resistance characteristic. Theconductive material is deposited to a sufficient thickness to fill atleast a part of the above-described openings H1, H2, H3, H4, H5, and H6.

Next, as illustrated in FIG. 10, the source and drain electrodes 217 aand 217 b, the capacitor upper electrode 314 of the pixel electrode 414,and the second pad electrode 517 are formed by patterning the thirdconductive layer 17 (FIG. 9). In detail, the source and drain electrodes217 a and 217 b and the second pad electrode 517 are formed bypatterning the third conductive layer 17 (FIG. 9) in a mask processusing a fourth mask (not shown). One of the source and drain electrodes217 a and 217 b, that is, the source electrode 217 a in the presentembodiment, is formed to connect the pixel electrode 414 via the openingH3 (FIG. 8) at the edge area of a second conductive layer 415 of theelectrode pattern 40 (FIG. 9) where the pixel electrode 414 is to beformed.

After the source and drain electrodes 217 a and 217 b are formed, thepixel electrode 414 and the capacitor upper electrode 314 are formed byadditional etching. In detail, the pixel electrode 414 is formed byremoving the second conductive layer 415, which is exposed by theopening H4, of the electrode pattern 40 (FIG. 9). The capacitor upperelectrode 314 is formed by removing the second conductive layer 315,which is exposed by the opening H5, of the electrode pattern 30 (FIG.9).

Thus, the gate lower electrode 214, the capacitor upper electrode 314,the pixel electrode 414, and the pad lower electrode 514 are formed ofthe same material and in the same layer. The capacitor lower electrode312 may be doped by injecting n-type or p-type impurities through theopening H5 (FIG. 8). The impurities injected during doping may be thesame as or different from one used during the doping of the active layer212.

Next, as illustrated in FIG. 11, a pixel define layer (PDL) 418 isformed on the substrate 10. In detail, a fourth insulation layer (notshown) is deposited on the entire surface of the substrate 10 where thepixel electrode 414, the source and drain electrodes 217 a and 217 b,the capacitor upper electrode 314, and the second pad electrode 517 areformed. The fourth insulation layer may be formed of one or more organicinsulation materials selected from a group consisting of polyimide,polyamide, acryl resin, benzocyclobutene, and phenol resin, in a methodsuch as spin coating. Also, the fourth insulation layer may be formed ofan inorganic insulation material selected from a group consisting ofSiO₂, SiN_(x), Al₂O₃, CuO_(x), Tb₄O₇, Y₂O₃, Nb₂O₅, and Pr₂O₃, inaddition to the above organic insulation material. The fourth insulationlayer may be formed in a multilayer structure in which the organicinsulation material and the inorganic insulation material arealternately arranged.

The PDL 418 for defining a pixel is formed by patterning the fourthinsulation layer in a mask process using a fifth mask (not shown) toform an opening H7 that exposes the center portion of the pixelelectrode 414 and an opening H8 that exposes the center portion of thesecond pad electrode 517.

Next, as illustrated in FIG. 12, the ion doping layer 517 a is formed bydoping ions such as nickel (Ni) or lanthanum (La) ions in the upperportion of the second pad electrode 517 exposed by the opening H8. Indetail, the organic light emitting display device according to thepresent embodiment includes the first pad electrode 515 and the secondpad electrode 517, in which the ion doped layer 517 a ischaracteristically formed on the upper surface of the second padelectrode 517 and will be described below in detail.

The requirements of a pad electrode may include a patterningcharacteristic, an electric characteristic, and pad reliability.Although there is a demand to develop a pad electrode that satisfies allthree requirements, no pad electrode satisfies all the requirementsuntil now. For example, when a pad electrode is configured in atri-layer structure of molybdenum (Mo)-aluminum (Al)-molybdenum (Mo),while a patterning characteristic with respect to wet etch is superior,Mo may be oxidized and a galvanic reaction occurs between Mo and Al sothat the pad reliability requirement may not be satisfied. When a padelectrode is configured in a tri-layer structure of titanium(Ti)-aluminum (Al)-titanium (Ti), while there is no worry of oxidizationand corrosion and a pad reliability is superior, it is a problem thatwet etch may not be employed. Also, when a pad electrode is formed in adual structure of Mo and Al only, an Al₂O₃ oxide is generated on asurface and thus Al is corrodes. That is, it is impossible to configurea pad electrode with the same material as one for forming a source/drainelectrode. To address this problem, a method of forming a pad electrodewith the same material as a pixel electrode in the same layer has beenconsidered, but it is a problem that a transparent electrode such as ITOforming a pixel electrode has too high resistance and a low structuralreliability.

To address the above problems, in the organic light emitting displaydevice according to the present embodiment, while the second padelectrode 517 is formed of the same material as the source and drainelectrodes 217 a and 217 b in the same layer, the ion doped layer 517 ais formed on the surface of the second pad electrode 517 so that thepatterning characteristic, the electrical characteristic, and the padreliability are all satisfied. That is, as ions such as nickel (Ni) orlanthanum (La) ions are doped in the upper portion of the second padelectrode 517 that is formed of a material such as aluminum (Al), theion doped layer 517 a which is a low resistance and simultaneouslycapable of functioning as a capping layer may be formed.

The ion doped layer 517 a may be formed by, for example, an ionimplantation process. That is, the ion doped layer 517 a is formed byinjecting ions such as nickel (Ni) or lanthanum (La) ions in the upperportion of the second pad electrode 517 that is formed of a materialsuch as aluminum (Al), as illustrated in FIG. 12. The accelerationvoltage of ions I being injected may be controlled such that the ions Imay be doped only in the surface and the upper portion of the second padelectrode 517, not in the entire portion of the second pad electrode517. For example, by controlling the acceleration voltage of the ionimplantation process at a level of about 10-40 keV, the ions I may bedoped only in the surface and the upper portion of the second padelectrode 517.

As such, since the ion doped layer 517 a prevents the second padelectrode 517 formed of a material such as aluminum (Al) from beingoxidized and corroded, the pad reliability may be improved.

It is preferred to perform ion doping only in the upper portion of thesecond pad electrode 517, not in the source and drain electrodes 217 aand 217 b. This is because, when ions are doped into pure aluminum,resistance may slightly increase. However, since the resistance of awiring should be low at its maximum in the source and drain electrodes217 a and 217 b, a slight increase in resistance may be problematic. Incontrast, the pad area is not much sensitive to the slight resistanceincrease and may have a characteristic of being strong to corrosionbecause the second pad electrode 517 is exposed to the outside. Thus,while the resistance of the source and drain electrodes 217 a and 217 bneeds to be maintained as low as possible by preventing the ion dopinginto the source and drain electrodes 217 a and 217 b that are sensitiveto the resistance increase, the second pad electrode 517 has a highanti-corrosion characteristic by performing ion doping into the secondpad electrode 517 that is sensitive to oxidization and corrosion.

As illustrated in FIG. 12, since the ion injection process is performedafter the PDL 418 is formed, even when ions are doped in the entiresurface of the organic light emitting display device, the ions are notdoped in the source and drain electrodes 217 a and 217 b that isprotected by the PDL 418, but only in the second pad electrode 517 thatis exposed to the outside, so that the ion doping layer 517 a where ionsare doped may be formed.

FIG. 13 schematically illustrates the shape of a pad electrode of anorganic light emitting display device manufactured by a manufacturingmethod of the present invention. FIG. 14 schematically illustrates theshape of a pad electrode of a conventional organic light emittingdisplay device, in which the pad electrode is formed in a tri-layerstructure of molybdenum (Mo)-aluminum (Al)-molybdenum (Mo).

Referring to FIG. 13, in the organic light emitting display devicemanufactured by a manufacturing method of the present invention, afterthe source and drain electrodes 217 a and 217 b and the second padelectrode 517 are all etched, it can be seen that a CD lateral skew isabout 1.2 μm and a taper angle after etching is an ideal angle of 72°.

In contrast, referring to FIG. 14, when a pad electrode is configured ina tri-layer structure of molybdenum (Mo)-aluminum (Al)-molybdenum (Mo),after the source and drain electrodes and the pad electrode are alletched, it can be seen that a CD lateral skew is about 1.59 μm and ataper angle after etching is 45° or less that is too much inclined. Assuch, when the taper angle too low, actually applied resistance mayincrease.

When a pad electrode is configured by the first pad electrode 515 formedof molybdenum (Mo), the second pad electrode 517 formed of aluminum(Al), and the ion doped layer 517 a that is doped with nickel (Ni) orlanthanum (La) ions and disposed on the second pad electrode 517, sinceresistivity of Al and AlNiLa is about 1/100 to ITO, resistance may bereduced to 1/1000 compared to a pad wiring in which a pad electrode isformed of ITO.

Also, comparing the present invention with the molybdenum (Mo)-aluminum(Al)-molybdenum (Mo) structure in terms of a wiring, it can be seen thatthe patterning characteristic of the present invention is improved, thatis, the CD lateral skew is improved to about 1.2 μm. Also, since thetaper angle approaches an ideal value after etching and the top portionof the pad is formed of AlNiLa, not Mo, it can be seen that the padelectrodes of the present invention may have a high anti-corrosioncharacteristic.

Also, when the pad electrodes of the present invention and the ITOstructure are compared, while the thickness of the pad electrode of thepresent invention is about 500 nm, the thickness of the ITO padstructure is merely about 30 nm so that it can be seen that thestructural stability of the present invention is much high. Therefore,according to the present invention, the patterning characteristic, theelectric characteristic, and the pad reliability of the pad portion areall satisfied.

Meanwhile, after the ion implantation process is performed asillustrated in FIG. 12, an annealing process is additionally performedto diffuse the injected ions so that a concentration profile accordingto a depth may become uniform.

FIG. 15 is a graph showing a concentration profile as a function of adepth after an ion implantation process. FIG. 16 is a graph showing aconcentration profile as a function of a depth after an annealingprocess is performed. As illustrated in FIGS. 15 and 16, rather thanperforming the ion implantation process only, when an annealing processis additionally performed, it can be seen that the concentrationdistribution of ions is uniform and smooth.

As illustrated in FIG. 2, the intermediate layer 419 including anorganic light emitting layer and the opposed electrode 420 are formed inthe opening H7 (FIG. 12) that exposes the pixel electrode 414. Theintermediate layer 419 may be formed by depositing an emissive layerEML, and at least one of other function layers such as a hole transportlayer HTL, a hole injection layer HIL, an electron transport layer ETL,and an electron injection layer EIL, in a single or combined structure.

The intermediate layer 419 may be formed of a low molecule organicmaterial or a polymer organic material. When the intermediate layer 419is formed of a low molecule organic material, the HTL and the HIL aredeposited in a direction toward the pixel electrode 414 with respect tothe organic light emitting layer and the ETL and the EIL are depositedin a direction toward the opposed electrode 420 with respect to theorganic light emitting layer. Also, a variety of layers may be depositedas necessary. A usable organic material may include copperphthalocyanine (CuPc), N,N′-Di(naphthalene-1-yl)-N,N′-diphenyl-benzidine(NPB), or tris-8-hydroxyquinoline aluminum (Alq3).

When the intermediate layer 419 is formed of a polymer organic material,the HTL only may be included in a direction to the pixel electrode 414with respect to the organic light emitting layer. The HTL may be formedon the pixel electrode 414 in a method such as inkjet printing or spincoating using poly-(2,4)-ethylene-dihydroxy thiophene (PEDOT) orpolyaniline (PANI). A usable organic material may include apoly-phenylenevinylene (PPV) based or polyfluorene based polymer organicmaterial.

The opposed electrode 420 may be formed as a common electrode by beingdeposited on the entire surface of the substrate 10. In the organiclight emitting display device according to the present embodiment, thepixel electrode 414 is used as an anode electrode and the opposedelectrode 420 is used as a cathode electrode. Also, the polarities ofthe electrodes may be reversely applied.

In a bottom emission type organic light emitting display device in whichan image is presented in a direction toward the substrate 10, the pixelelectrode 414 is a transparent electrode and the opposed electrode 420is a reflection electrode. The reflection electrode may be formed bythinly depositing metal having a low work function, for example, Ag, Mg,Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/Ca, LiF/Al, or a compoundthereof.

During each mask process for forming the above-described organic lightemitting display device, a deposition layer may be removed by dryetching or wet etching. In the above-described embodiment, an organiclight emitting display device is described as an example. However, thepresent invention is not limited thereto and a variety of displaydevices including a liquid crystal display device may be employed. Also,although one TFT and one capacitor are illustrated in the drawings thatillustrate the embodiment according to the present invention, this isfor convenience of explanation and the present invention is not limitedthereto. A plurality of TFTs and a plurality of capacitors may beincluded without increasing the number of mask processes according tothe present invention.

As described above, according to the organic light emitting displaydevice according to the present invention, a manufacturing process issimplified, and all of a patterning characteristic, an electricalcharacteristic, and a pad reliability of a pad unit are satisfied.

While this invention has been particularly shown and described withreference to exemplary embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention as defined by the appended claims.

1-15. (canceled)
 16. A method of manufacturing an organic light emittingdisplay device, the method comprising: forming an active layer on asubstrate via a first mask process operation, the substrate having alight emitting area and a non-light emitting area that is disposedoutside the light emitting area to surround the light emitting area, theactive layer being formed in the light emitting area of the substrate;forming a gate electrode and a first pad electrode via a second maskprocess operation, and an electrode pattern that forms a pixelelectrode, above the active layer, the gate electrode and the electrodepattern being formed in the light emitting area of the substrate, thefirst pad electrode being formed in the non-light emitting area of thesubstrate; forming an interlayer insulation layer having an opening thatexposes both sides of the active layer, via a third mask processoperation, a part of the first pad electrode, and a part of theelectrode pattern; forming source and drain electrodes contacting bothexposed sides of the active layer via a fourth mask process operation, asecond pad electrode contacting an exposed part of the first padelectrode, and the pixel electrode, the second pad electrodeelectrically connected to the first pad electrode, the source and drainelectrodes being formed in the light emitting area of the substrate, thesecond pad electrode being formed in the non-light emitting area of thesubstrate; forming a pixel define layer that exposes at least a part ofthe pixel electrode and at least a part of the second pad electrode viaa fifth mask process operation; and doping predetermined ions in atleast a part of the exposed second pad electrode.
 17. The method ofclaim 16, wherein the doping of predetermined ions in at least a part ofthe exposed second pad electrode is performed by an ion implantationprocess.
 18. The method of claim 17, wherein the ion implantationprocess is performed by applying an acceleration voltage of about 10-40keV.
 19. The method of claim 16, wherein, in the doping of predeterminedions in at least a part of the exposed second pad electrode, the ionsare doped only in a surface and an adjacent area of the second padelectrode opposite to a surface facing the substrate.
 20. The method ofclaim 16, wherein the doping of predetermined ions in at least a part ofthe exposed second pad electrode is performed in a state in which thesource and drain electrodes are covered by the pixel define layer. 21.The method of claim 16, wherein the first pad electrode comprisesmolybdenum (Mo), the second pad electrode comprises aluminum (Al), andthe ions doped in the ion doped layer comprise at least one of nickel(Ni) and lanthanum (La) ions.
 22. The method of claim 16, wherein anannealing process operation of diffusing the injected ions is performedafter the doping of predetermined ions in at least a part of the exposedsecond pad electrode.
 23. The method of claim 16, wherein the secondmask process operation comprises: sequentially depositing a secondinsulation layer, a first conductive layer, and a second conductivelayer above the active layer; and forming the gate electrode comprisingthe first conductive layer as a gate lower electrode and the secondconductive layer as a gate upper electrode and simultaneously formingthe first conductive layer as a pad lower electrode and the secondconductive layer as a first pad electrode, by patterning the firstconductive layer and the second conductive layer.
 24. The method ofclaim 16, wherein the third mask process operation comprises: depositinga third insulation layer on the gate electrode, the first pad electrode,and the electrode pattern; and forming an opening by patterning thethird insulation layer, the opening exposing parts of source and drainregions of the active layer, a part of the first pad electrode, and apart of the electrode pattern.
 25. The method of claim 16, wherein thefourth mask process operation comprises: depositing a third conductivelayer on the interlayer insulation layer; and forming the source anddrain electrodes and the second pad electrode by patterning the thirdconductive layer.
 26. The method of claim 16, wherein the fourth maskprocess operation further comprises: forming the source and drainelectrodes and the second pad electrode; and forming the pixel electrodecomprising the first conductive layer as an electrode by removing thesecond conductive layer constituting the electrode pattern.
 27. Themethod of claim 16, wherein the fifth mask process operation comprises:depositing a fourth insulation layer on an entire surface of thesubstrate; and forming the pixel define layer by patterning the fourthinsulation layer.